Various aircraft, including both civilian aircraft and military aircraft, share the navigable airspace. To avoid mid-air collisions, a portion of the navigable airspace, typically referred to as “controlled airspace,” is controlled by ground-based air traffic control. Air traffic control communicates with aircraft pilots to effect an orderly flow of air traffic and to avoid both mid-air and on-the-ground collisions. Outside of controlled airspace, aircraft pilots avoid collisions by relying on their sight and sophisticated sense and avoid equipment, such as a traffic collision avoidance system (TCAS) and an automatic dependent surveillance-broadcast (ADS-B).
The introduction into the navigable airspace of unmanned aircraft, such as unmanned aerial vehicles (UAVs or drones), presents concerns of unmanned aircraft-to-manned aircraft collisions, as well as unmanned aircraft-to-unmanned aircraft collisions. These concerns have become more acute with the proliferation of unmanned aircraft and the growing interest in using unmanned aircraft for commercial purposes, such as surveillance (e.g., agricultural surveillance and law enforcement surveillance) and product delivery.
Unmanned aircraft are piloted by ground-based pilots. Therefore, in the case of unmanned aircraft, the ability to use pilot sight to avoid mid-air collisions is drastically reduced, if not completely eliminated. Sophisticated sense and avoid equipment may provide a level of security, but such equipment is expensive and increases vehicle weight, which is a significant concern for already-lightweight unmanned aircraft.
Accordingly, those skilled in the art continue with research and development efforts in the field of airspace deconfliction.